Accession Number : AD0428131


Title :   AN ELECTRON MICROSCOPE INVESTIGATION OF FATIGUE FRACTURES IN A HIGH-STRENGTH SHEET STEEL,


Descriptive Note : Memo. rept.


Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C


Personal Author(s) : Dahlberg,E P


Report Date : Feb 1962


Pagination or Media Count : 12


Abstract : The electron microscope was used to study the fracture surfaces of center-slotted sheet steel specimens that were tension-tension fatigued to failure. Typical fatigue fracture markings were found on the slow crack growth regions of annealed specimens but were not found on the same regions of hardened and tempered specimens. The transition from slow crack growth to rapid fracture propagation in the hardened specimens took place over an extended length of the fracture surface. Alternating areas of slow and rapid fracture propagation produced a banded structure in this transition zone. (Author)


Descriptors :   *STEEL , *FRACTOGRAPHY , FRACTURE(MECHANICS) , ELECTRON MICROSCOPY , SHEETS , FATIGUE(MECHANICS) , PLASTIC PROPERTIES , DEFORMATION , BRITTLENESS , STRESSES


Distribution Statement : APPROVED FOR PUBLIC RELEASE